The crew contracted to remove the controversial “drum major” quote from the Martin Luther King Jr. Memorial has hit a snag as the 50th anniversary of King’s March on Washington for Jobs and Freedom approaches.

Sculptor Master Lei Yixin successfully chiseled over the paraphrased quote, “I was a drum major for justice, peace and righteousness,” on the sculpture to appease critics in time for the Aug. 28 anniversary of King’s “I Have a Dream Speech,” but subsequent blasting work needed to smooth out the texture of the stone has been stalled.

Historic building restoration contractor Worcester Eisenbrandt, Inc., a Baltimore-based firm hired by the National Park Service, does not have the insurance required to complete the sandblasting in its contract for the project, NPS spokeswoman Carol Johnson said on Tuesday.

Workers tried an alternate approach, using walnut shells to smooth the stone, but the technique left an “oily” stain on the surface of the monument, Johnson said.The Associated Press reported the snag on Monday evening.

“When we did the contract we were unaware that this was going to need aggregate blasting,” Johnson said. The National Park Service was not involved in the initial construction of the 30-foot likeness of King. The agency took possession of the monument for the August 2011 dedication.

Yixin was flown in from China in late July to make changes to the statue. It was not until after the work started that the NPS was alerted of the need for sandblasting, Johnson said. Now the NPS is working to see if the agency’s Historic Preservation Training Center can complete the work with Yixin before he departs for China on Aug. 20. If that doesn’t work, the agency will work with Yixin to finish the work after the anniversary events on Aug. 28.

Scaffolding currently surrounding the King Memorial will be removed for the anniversary celebration, even if the project is not yet completed, Johnson said.